Electrocatalysis for the Direct Alcohol Fuel Cell

Léger, J. M.; Coutanceau, Christophe; Lamy, C.

doi:10.1002/9780470463772.ch11

Cited by 8 publications

(10 citation statements)

References 104 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…First, we briefly discuss the IR spectra obtained during methanol electrooxidation on samples I (Pt(111)), III (Pt(8%)–CeO 2 /Au), and IV (Pt(15%)–CeO 2 /C/Au) at pH 1 (0.1 M perchloric acid). The reaction mechanism in acidic solution was investigated in great detail. ,− Two different pathways have been identified, the so-called direct and the indirect. In the direct pathway methanol is oxidized to CO 2 via partially oxidized intermediates, while in the indirect pathway adsorbed CO (CO ads ) is formed as an intermediate, which poisons the catalyst.…”

Section: Resultsmentioning

confidence: 99%

Stabilization of Small Platinum Nanoparticles on Pt–CeO₂Thin Film Electrocatalysts During Methanol Oxidation

et al. 2016

View full text Add to dashboard Cite

Pt-doped CeO x thin film electrocatalysts have recently been shown to exhibit high activity and stability at the anode of proton exchange membrane fuel cells (PEM-FC). To identify the role of the Pt dopant and the origin of the high stability of Pt–CeO x films, we applied electrochemical in situ IR spectroscopy on Pt–CeO x model thin film catalysts during methanol (1 M methanol) oxidation. The model catalysts were prepared by magnetron cosputtering of Pt (9–21 atom %) and CeO2 onto clean and carbon-coated Au supports. All samples were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) before and after reaction. At pH 1 (0.1 M HClO4) the Pt–CeO x dissolves partially during potential cycling, whereas the films are largely stable at pH 6 (0.1 M phosphate buffer). Electrochemical IR spectroscopy of the adsorbed CO shows that metallic Pt is formed on all Pt–CeO x samples during methanol oxidation. In comparison to Pt(111), Pt aggregates on Pt–CeO x show a CO on-top signal, which is red shifted by at least 25 cm–1 and suppression of the bridging CO signals. Whereas the Pt particles on Pt–CeO x films with high Pt concentration (>20 atom %) undergo rapid sintering during the potential cycling, small metallic Pt aggregates are stable under the same conditions on films with low Pt concentration (<15 atom % Pt). By means of density functional theory (DFT) calculations we analyzed the spectral shifts of adsorbed CO as a function of nanoparticle size both on free and ceria-supported Pt particles. Comparison with the experiment suggests the formation of “subnano”-particles, i.e., particles with up to 30 atoms (<1 nm particle diameter), which do not expose regular (111) facet sites. At sufficiently low Pt loading, these subnano-Pt particles are efficiently stabilized by the interaction with the ceria support under conditions of the dynamically changing electrode potential.

show abstract

Section: Resultsmentioning

confidence: 99%

Stabilization of Small Platinum Nanoparticles on Pt–CeO₂Thin Film Electrocatalysts During Methanol Oxidation

et al. 2016

View full text Add to dashboard Cite

show abstract

“…This raises questions regarding the reaction mechanism, kinetics, and potential side reactions. While many studies have addressed the electrooxidation of small primary alcohols such as methanol ,− and ethanol, ,− much less is known about the electrooxidation of secondary alcohols such as IPA.…”

Section: Introductionmentioning

confidence: 99%

Secondary Alcohols as Rechargeable Electrofuels: Electrooxidation of Isopropyl Alcohol at Pt Electrodes

et al. 2020

View full text Add to dashboard Cite

Fuel cells can be operated directly by oxidation of isopropyl alcohol (IPA) to acetone (ACE). If the product ACE is hydrogenated, IPA is formed again. In this way, IPA serves as a rechargeable electrofuel. In this work, we study the oxidation of IPA at Pt electrodes using several complementary experimental methods, including cyclic voltammetry (CV), electrochemical real-time mass spectrometry (EC-RTMS), and electrochemical infrared reflection absorption spectroscopy (EC-IRRAS), in combination with density functional theory (DFT) to assign the vibrational modes of IPA and ACE. Different types of Pt electrodes are investigated, namely single crystalline Pt(111) surfaces, polycrystalline Pt, and nanostructured tubular Pt electrodes. The onset of the IPA oxidation on the Pt electrodes is observed at 0.3 VRHE, yielding ACE with high selectivity. At potentials above 0.9 VRHE, the formation of Pt oxide inhibits the reaction. The only side reaction observed is the formation of small amounts of CO2. We show that adsorbed ACE is formed at the Pt electrodes poisoning the surface. On nanotubular electrodes with high surface area, ACE stays mainly adsorbed on the surface, and only a small fraction desorbs. These observations suggest that poisoning of the Pt electrode by adsorbed ACE limits the oxidation of IPA.

show abstract

“…The improvement of the catalytic activity and selectivity of palladium electrocatalysts is generally realized by increasing the active surface area of the catalyst and by the addition of a second metal with a promotional effect. , In the case of alcohol electro-oxidation in alkaline media, it has been shown that interactions between palladium and bismuth modified the electrocatalytic properties, − although the kind of interactions is not yet fully understood. In particular, the bismuth deposition mode and the resulting composition of the Bi deposit, the interaction with the substrate, and so forth have an impact on the activity and selectivity of the Pd modified catalysts. , …”

Section: Introductionmentioning

confidence: 99%

Self-Supported Pd_xBi Catalysts for the Electrooxidation of Glycerol in Alkaline Media

et al. 2014

View full text Add to dashboard Cite

Highly active self-supported PdxBi catalysts are synthesized by the sacrificial support method. Self-supported PdxBi catalysts have a porous nanostructured morphology with high surface areas (in the range from 75 to 100 m(2) g(-1)), making PdxBi a state-of-the-art catalyst. Pd4Bi displays the highest activity toward glycerol oxidation. In situ Fourier transform infrared spectroscopy highlights the unique catalytic behavior of self-supported PdxBi materials due to their particular structure and morphology. The confinement of reactants and intermediates in pores acting as nanoreactors is responsible for the high selectivity as a function of the electrode potential: aldehyde and ketone at low potentials, hydroxypyruvate at moderate potentials, and CO2 at high potentials. Moreover, the selectivity depends on the electrode history: it is different for the positive potential scan direction than for the reverse direction, where the catalyst becomes selective toward the production of carboxylates.

show abstract

Electrocatalysis for the Direct Alcohol Fuel Cell

Cited by 8 publications

References 104 publications

Stabilization of Small Platinum Nanoparticles on Pt–CeO₂Thin Film Electrocatalysts During Methanol Oxidation

Stabilization of Small Platinum Nanoparticles on Pt–CeO₂Thin Film Electrocatalysts During Methanol Oxidation

Secondary Alcohols as Rechargeable Electrofuels: Electrooxidation of Isopropyl Alcohol at Pt Electrodes

Self-Supported Pd_xBi Catalysts for the Electrooxidation of Glycerol in Alkaline Media

Contact Info

Product

Resources

About

Electrocatalysis for the Direct Alcohol Fuel Cell

Cited by 8 publications

References 104 publications

Stabilization of Small Platinum Nanoparticles on Pt–CeO2Thin Film Electrocatalysts During Methanol Oxidation

Stabilization of Small Platinum Nanoparticles on Pt–CeO2Thin Film Electrocatalysts During Methanol Oxidation

Secondary Alcohols as Rechargeable Electrofuels: Electrooxidation of Isopropyl Alcohol at Pt Electrodes

Self-Supported PdxBi Catalysts for the Electrooxidation of Glycerol in Alkaline Media

Contact Info

Product

Resources

About

Stabilization of Small Platinum Nanoparticles on Pt–CeO₂Thin Film Electrocatalysts During Methanol Oxidation

Stabilization of Small Platinum Nanoparticles on Pt–CeO₂Thin Film Electrocatalysts During Methanol Oxidation

Self-Supported Pd_xBi Catalysts for the Electrooxidation of Glycerol in Alkaline Media